The nice thing about the PCV is that it runs the corrosive crankcase gasses back through the engine, they get burned, and dumped out with the exhaust (I'm sure you knew that, but I'm just reiterating). A breather just leaves them to hang around in your engine bay, and eventually deposits or drips form around and under the breather. The breather looks cool, but the PCV system works better and actually cleaner in the long run. That and, like stated above, the PCV system sort of "sucks" the gasses out of the crankcase, where a breather just lets them float out as they come, which can theoretically shorten the life of your oil.
That being said, there is nothing wrong with a breather, a PCV system is just a nicer option.
